62-12259 7–54
00123 Check Supply Air Sensor
• ACTIVATION: Supply Air Temperature Sensor (SAT) is not within range of -53 to +158°F (-47 to +70° C).
• UNIT CONTROL: Engine and Electric Operation:
• If alarm 00122 Check Return Air Sensor is not active: Temperature Control is set for Supply Air and
setpoint is in the perishable range: Alarm and switch to return air control.
• If alarm 00122 Check Return Air Sensor is active: alarm and the System will enter Cargo Protect
Mode. Refer to Section 4.10.2.
• RESET CONDITION: Auto reset when sensor is in range or, alarm may be manually reset using the
display mounted keys or by turning the unit off and then back on again.
NOTE
Follow the steps below until a problem is found. Once a repair or correction has been made, the
active alarm should clear itself (refer to reset condition above). Operate the unit through the appro-
priate modes to see if any active alarm occurs. Continue with the steps below as necessary.
Corrective Actions:
1. Check Sensor
a. Inspect sensor and connectors. Verify there is no damage to sensor, and no damage, moisture, or
corrosion in connectors.
b. Check sensor resistance. (Refer to Note 3 in Notes Section) 10,000 Ohms @ 77°F (25°C). Refer to
Table 8–5 for chart of resistances for different sensors.
2. Check Sensor Wiring
a. Inspect connector pins and terminals at sensor connector
1-3MSM-4 and 16
. (See wiring
schematic
Section 10.2
) Verify there is no physical damage to harness, and no damage, moisture,
or corrosion in connectors.
b. Place the system in PC Mode. Refer to Note 2 in Notes Section Disconnect sensor from harness.
Check for 3.0 ± 0.1 VDC volts at harness plug between pins. This verifies microprocessor output and
wiring connections to the sensor.
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